Tayside Diabetes MCN Handbook
Management of Intercurrent Illness in Type 1 Diabetes


THE GOLDEN RULE: Insulin should NEVER be omitted due to the risk of Diabetic Ketoacidosis (DKA)

ALWAYS check for ketones

EXTRA DOSES of rapid acting insulin are often required during illness.

This advice applies to adults.  for children under the age of 16 years contact the Paediatric Diabetes Team.

Algorithm for Hyperglycaemia in Adults


Food and Fluids during Illness

  • Maintain an adequate fluid intake (sugar free) of 100-200mL (approximately 1 glass) every hour
  • Maintain a regular intake of carbohydrate, regardless of blood glucose to facilitate insulin administration; insulin is required to correct ketosis.
  • At mealtimes, if unable to eat, but tolerating fluids, take carbohydrate in the form of 200mL of the following: pure fruit juice, ribena, milk, milk with drinking chocolate or ovaltine, (flat) Coca Cola or Lemonade (sugary).
  • If vomiting, consider an anti-emetic injection.  Provide with 'Dioralyte' or 'Rehidrat'.  Instruct to reconstitute as directed and to take an egg-cupful every 10 minutes.
  • Hospital admission is indicated if unable to swallow or keep fluids down (view below).


Blood Glucose Monitoring

  • Ensure that glucose monitoring technique and equipment is accurate and available.
  • Increase the frequency of blood glucose monitoring to at least 4 hourly.
  • Arrange to review results with patient.  See contact numbers for Diabetes Specialist Nurses


Ketone Monitoring

  • Check ketones in patients who are acutely unwell, vomiting and / or during pregnancy, irrespective of BG level. An elevated ketone result identifies the risk of Diabetic Ketoacidosis (DKA.)
  • Ketonuria/Ketonaemia is an early sign of decompensation and if acted upon promptly, can often prove possible to avert hospital admission (view below). Algorithm for Hyperglycaemia in adults.
  • Ketones should be checked 2 - 4 hourly during acute illness.
  • Ketostix (Bayer Diagnostics) reagent strips for urine testing
  • Optium B-ketone test strips for blood ketone testing with Optium Neo meter (Abbot).
  • Glucomen Lx plus ketone sensors for blood ketone testing with Glucomen Lx meters (Menerini)
  • All people with type 1 diabetes should be informed and educated in ketone monitoring

Blood ketone meter and urine dipsticks measure different ketone bodies.

Blood ketone testing identifies the 'immediate situation' and is more reliable than urine ketone testing which provides 'retrospective' information. Blood ketone meters measure BHydroxybutyrate and this is the predominant ketone in DKA. Urine dipsticks measure acetoacetate, hence a negative urine ketone result does not rule out ketosis. It is important to note that during treatment for DKA conversion of B-hydroxybutyrate to acetoacetate may initially result in a paradoxical rise in urine ketones. Blood and ketone testing therefore are not strictly interchangeable.


SGLT2 Inhibitors and Diabetic Ketoacidosis (DKA)


Those taking SGLT2 inhibitors are at greater risk of DKA during intercurrent illness.

Provide your patients with the following information: It is suggested that SGLT2 inhibitors are withheld for the period you are unwell.  It is likely that you will require a 10 - 20% increase in insulin doses whilst these drugs are withheld.

Please follow this link for more information.



Interpretation of ketone results during illness

Blood ketone level
Blood ketone level less than 0.6 mmol/L

This is within the normal range.

During illness test again in 2-4 hours to re-assess.

Blood ketone level greater than 0.6 mmol/L
Consider extra insulin by increasing routine insulin dose by 10% if blood glucose levels are elevated.
Consider STAT dose of rapid acting insulin (see below)
Recheck blood glucose and ketone level again in 1-2 hours to assess.


Indications for hospital admission

  • Inability to swallow or keep fluids down.
  • Persistant vomiting.
  • Persistant diarrhoea.
  • Strongly positive ketonuria/ketonaemia with or without hyperglycaemia
  • When ketoacidosis is clinically obvious i.e. dehydration, abdominal pain, intractable vomiting, rapid or laboured respirations.



Insulin Management

  • More insulin is often required during illness
  • Increase routine insulin if the trend of recent blood glucose levels are elevated, see insulin adjustment
  • During illness extra insulin can be administered 2-4 hourly to address elevated blood glucose levels (in addition to routine insulin doses)
  • Insulin is required to correct ketosis
  • If ketosis is evident with low or normal blood glucose levels (e.g. in patients who are vomiting) IV fluid and insulin is indicated and patient should be admitted to hospital
  • Always recheck blood glucose and ketones within two hours to assess improvement or deterioration


Guidance for Calculation of extra rapid acting insulin

Increase 'usual' insulin by 10% if the recent trend of BG>10mmol/L

Extra insulin can correct hyperglycaemia and clear ketones

Use short acting nsulin for STAT dosing e.g. Actrapid / Novorapid / Humalog /Apidra

Calculate STAT dose as 10-20% of the patient's daily dose of insulin

For example: if the total daily insulin dose is 40 units, 10-20% will be a dose of 4-8 units

Recheck blood glucose and ketones in 1-2 hours

STAT doses can be repeated at intervals of 2-4 hours if needed

OR some patients will calculate a correctional insulin dose


  • 100 divided by total daily insulin dose e.g.
  • If the total daily insulin dose is 50 units
  • 100 divided by 50 = 2
  • Therefore assume 1 unit of insulin will reduce (correct) the blood glucose by 2mmol/L
  • Example: if the blood glucose level is 20mmol/L, assume 5 units of rapid acting insulin will correct blood glucose to 10mmol/L
  • Aim to correct blood glucose to 10mmol/L
  • Blood glucose monitoring will identify the efficacy of this management. 


Medicines Sick Day Rules (Renal)

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Follow up and Advice

The hospital diabetes team is available to advise.

Diabetes Specialist Nurses can provide ‘sick day rules’ advice and follow up